Directionally stiff woven fabric and method



Oct. 1946- R. c. WHITMAN 2,409,089

DIRECTIONALLY STIFF WOVEN FABRIC AND METHOD Filed May 17, 1943 2 ShecLs-Sheet l N n N 3 fi 0 miim INVENTOR.

ATTORNEY Oct. 8, 1946. R. c. WHlTMAN DIRECTIONALLY STIFF WOVEN FABRIC AND METHOD Filed May 17, 194;

' 2 Sheets-Sheet S and Z GROUP YARN TWIST Com:

E N O C T m w T Z INVENTOR.

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Patented a. a, 1946 2,409,089

umrso s'rA'rss PATENT OFFICE DIRECTIONALLY STIFF WOVEN FABRIC AND METHOD Ross C. Whitman, Walpole, Mesa, asslgnor to The Kendall Company, Boston, Mass a corpoi-ation of Massachusetts Application May 17, 1943, Serial No. 487,360 18 Claims. (Cl. 139-420) This invention relates to directionally stiff Fig. 3 is a perspective view illustrating a step woven fabrics and methods of making the same. in the manufacture of certain of the herein The object of the invention is to provide fabrics described fabrics having materially greater stiffness in one direc- In accordance with my invention, ther may tion than in another, that is, fabrics that are rel- 5 be produced a wide variety of fabrics, all exatively stiff in one direction, and limp, or at any hibiting a significant, controlled, uniform and rate much less flexible, at rightangles to that predetermined degree of directional stiffness. direction, and, moreover, fabrics which have little This, I have discovered, may be accomplished by or no curling tendency. chemically treating the yarns of the woven fab- There are numerous uses for such fabrics hav- Tie selectively and thereby making one set of ing significantly greater stiffness in one yarn yarns many times stiffer than the other-based direction than in the other, for instance, collars on the principle that one set of yarns can be renand cuffs require a considerably higher degree of dered reactive to a chemical treating or impregvertical stiffness than horizontal stiffness. They nating agent, while the other set will not be maare necessarily curved in the latter direction and 5 terially affected by it, or at any rate, will be afexcessive horizontal stiffness, particularly in a fected to a ve y much d en and l sser decollar, is a source of trouble and irritation. Cergree, so as to provide the significant difference tain curtain fabrics should be stiff up and down in relative stiffness as hereinafter more fully set and soft crosswise in order to hang attractively, forth. Surprising variations in the stiffnes of while others have a better drape if they are stiff 2o yarns in the same fabric, which yarns may even crosswise or in a horizontal direction. Many have fundamentally the same chemical compoclothing interliners also should be stiff in one sition, can be produced by taking advantage of direction only, and a considerable variety of the differences in susceptibility to chemical accommonly usedfabrics would be improved were tion which they can be made to exhibit, and it possible to provide and predetermine direcsuch differential action utilized in producing the tional stiffness therein. novel fabrics of my invention.

Whil numerous fabrics are slightly stifier in For example, if a cotton fabric is made with one direction than in the other, due usually to the f a warp consisting of unscoured or gray" cotton fact that the yarns of one set are larger and more yarn, and the filling also i of cotton but is numerous than the yarns or threads of the other scoured and bleached, it is then entirely feasible set, any trifling differences in stiffness so proto gelatinize the secured or bleached cotton yarns duced are customarily not material or significant. by impregnating the fabric with a fusing agent, Also, as a rule, they are not contemplated or dea solution of zinc chloride for example, and thus sired, but, instead, occur simply as incidents of stiffen the latter yarns to a very substantial deth method of manufacture (for example, in progree without producing any marked effect on the ducing pattern or other visual effects), or the nagray yarns. The difference in the reactivity of ture of the materials used, and both are conthe bleached and unbleached cotton fibers to the trolled by other considerations, primarily those action of fusing agents apparently is du priof economy, marily to the fact that raw cotton contains con- The usual methods of stiffening fabrics by 40 siderable amounts of natural waxes, oils, or simcoating them with starch or other water-soluble ilar protective agents which render the unsubstances, or with water-insoluble stiffening hlleached cotton fibers relatively inert to the agents, such as some of the synthetic resins, proaction of zinc chloride and other gelatinizing or duce their stiffening effect without any material fusing agents. Later, these protective constitudirectional characteristic, and offer no solution ents can be removed, as by kier boiling, and the for the problems of directional stiffness with entire fabric thus can be made to present a subwhich this invention is concerned. The same is stantially uniform and entirely satisfactory aptrue of chemical processes devised heretofore for pearance.

the purpose of stiffening fabrics. The same general reaction to gelatinizing re- In the drawingsagents is exhibited by many common textile Fig. l is a diagrammatic view of a preferred fibers, filaments, and yarns made therefrom.

form of fabric made in accordance with this For example, in such a fabric as that just deinvention; scribed, the bleached or scoured cotton yarns can Fig. 2 is a diagrammatic view of another prebe replaced by yarns of scoured linen, sisal,ramie,

ierred form of fabric of the invention; and hemp, Jute, and other natural cellulosic fibers.

Viscose, cuprammonium, and other regenerated cellulose yarns (either cut staple or continuous filament) give essentially the same results. I have also found that yarn made from cellulose ester fibers (either cut staple or continuous fila ment), such as cellulose acetate, cellulose butyrate, and cellulose propionate, or mixtures or copolymers of the same, are satisfactory as the stiffened yarns.

Yarns normally relatively non-reactive to such gelatinizing agents may be made from raw cotton fibers, or any of the common vegetable textile fibers which have not been scoured, woolor Aralac ("casein wool), nylon, or other noncellulosic synthetic fibers r filaments, such as vinyl acetate and vinyl chloride copolymers, and vinylidene chloride, for example, those sold under the respective names of Vinyon and Saran. Or, the reactive fibers or yarns before referred to can be mad sufficiently non-reactive for the purposes of this invention by treating them with protective agents, such as small proportions of waxes, oils, fatty materials, or other temporary agent, or with permanent agents such as formaldehyde, or formaldehyde containing resins, e. g., urea formaldehyde 0r phenol formaldehyde, so that the gelatinizing agent cannot readily reach or attack the bare fibers.

In practice it is found that this invention is equally applicable to a considerable range of fabrics in which the yarns are selected with their differential chemical reactivity characteristics in mind. For gelatinizing or fusing agents a number of chemicals, known and used in the textile art as fusing agents, are equivalents. For example, in treating the cotton fabric above referred to, such swelling agents as cuprammonium (copper tetramine hydroxide) or sulphuric acid can be used in place of the zinc chloride. Other examples are mixed acids" (nitric and sulphuric), phosphoric acid, the quaternary ammonium bases, a caustic soda solution at C., calcium thiocyanate, and others. Naturally, no strongly alkaline fusing agent should be used on fabrics which include wool or Aralac type fibers. The action of fusing agents on cellulose fibers, such as scoured cotton and rayon, is well known in the cloth finishing trade and is variously referred to as swelling, fusing, gelatinizing or parchmentizing- Th methods or processes followed in using these various agents differ but the conditions have been thoroughly worked out for each of them and are well known to those experienced in the trade, although none has ever been used-heretofore, so far as I am aware, for this particular purpose of selectively stiffening 'to produce the directionally stiff fabrics of this invention. For example, fabrics to be fused with zinc chloride are usually exposed to this material for a number of hours, whereas goods of a cellulosic composition when processed with sulphuric acid are treated with thi reagent for only a few seconds.

The reaction desired for the purposes of this invention in all of these treatments is a combined swelling and superficial solubilizing effect, producing some adhesion of the fibers to each other, usually to a considerable depth in the thread or yarn. Whexi this reaction has proceeded to the desired degree, the gelatinizing agent is neutralized or removed and the fabric is thoroughly washed and dried.

For convenience such reagents as those above referred to will hereinafter be referred to usually.

as fusing" agents or as gelatinizing agents,

tendency, or even its and the effect of them will be referred to as a fusing or a gelatinizationl' or the yarns will be described as being fused," gelatinized" or stiffened," it being understood that these terms may not be used in a-scientiflcally accurate sense.

In making directionally stiffened fabrics, it was found that the fabrics treated in this manner in early experimental work showed an-exasperating curl, which curl evidences itself by two diagonally opposite corners of a squar piece of fabric rolling upwardly and towards each other, scroll-like, the axi of the scroll being diagonal and connecting the remaining two corners which tend to curl downwardly. In fact, these remaining tw corners, if permitted, form an opposite scroll with a curling axis approximately at right angles to the axis of the scroll first referred to. As a result of a series of experiments undertaken to determine the reason for this surprising and undesirable result, I found that this characteristic curl is produced by a tendency of the stiffened yarns to rotate individually, and, strangely, because of a tendency of the stiffened yarns for some reason to twist more tightly as a result of their gelatinization, for it naturally had been supposed that the gelatinization would simply produce the effect of setting the fibers and eliminate any tendency of the yarns to twist in one direction or the other.

The direction of the fabric curl caused by this phenomena of the fused yarns twisting more tightly was discovered to depend upon which direction the fused yarns twist, for example, in a fabric having gray warp yarns and fused filling yarns of uni-directional Z or right-hand twist wherein the filling yarns tend to twist tighter counter-clockwise as a, result of fusing treatment, the right-hand corner of the fabric (viewed with the filling yarns in end elevation and twisting tighter counter-clockwise) lifts and curls up wardly with the left-hand corner of the fabric curling downwardly. Similarly, if, in this fabric the fused filling yarns were of uni-directional s twist, the left-hand corner of the fabric lifts, etc.

It was then found that control of the curling elimination, could be achieved in several different ways, and that the controlling factor in the curl of a directionally stiff fabric is the bleached cotton or other reactive yarns since these are the yarns in which the tendency to twist tighter and curl the fabric is strongly increased by the chemical treatment. My preferred manner of dealing with curl is to use like or similar oppositely-twisted reactive 'yarns in approximately equal amounts either in the warp or in the filling, according to which direction the fabric is to be stiffened. That is, to balance or neutralize the curling tendencies of the right-hand or Z twist yarns which are to be stiffened one should use an equal number of similar left-hand or S twist yarns. This can be accomplished in either warp or filling (according to in which yarn direction it is desired to stiffen the fabric), by 'weaving alternate twist singles (or pairs of singles) yarns, or by weaving groups of yarns in lieu of singles as alternate twist groups in the fabric, each group in this case including all 8 yarns or all 2 yarns. Preferably, however, there are included both 8 and Z twist yarns in the same or adjacent groups. In practice, and to avoid the use of a box loom if single 8 and Z twist yarns (or S twist groups and Z twist groups) be used in the filling, it is frequently preferable and much more economically accomplished in an ordinary loom by a method of weaving in which the bobbin trails, on each pick, a plurality, of oppositely twisted yarns, for example, one 8 and one 2 yarn may be deposited together, one shuttle movement or shot thus'producing two ends in the cloth. An example of such a fabric is diagrammatically shown in Fig. 1 of the drawings in which the warp yarns 2 have woven across them filling yarns I, as just, described, with each pick includingtwo yarns, one 8 and one 2, these yarns being wound together on the bobbin or quill, and preferably in the novel manner shown in Fig. 3, as hereinafter more fully described. Similarly, in Fig. 2, the gray warp yarns 6 have woven across them fillings 8, each successive pick of which includes four yarns, two 8 twist and two 2 twist, all taken from the same bobbin or quill on which they have been wound in the manner of Fig. 3.

In order to provide on a single bobbin oppositely twisted yarns which will unwind evenly as they are pulled ofl the end of the bobbin or quill and provide a composite group yarn which will not produce fabric curl, it has been found highly desirable in commercial practice to wind them on the quill in a certain manner so that one yarn, to some extent at least, is wound about the oppositely twisted yarn. I have found that this may conveniently be done in the manner shown in Fig. 3 in which the Z twist cone is placed beneath and the yarn led therefrom up through the bore of the S twist cone so, as the Z yarn emerges, the S twist yarn is attached to and wound about it and the two are drawn off together and then wound on a bobbin or quill 5. This can be accomplished as described when the Z twist and S twist cones have both been wound in the same direction, namely, counter-clockwise,

as viewed from above or in plan, so that the unwinding, as shown in Fig. 3, takes place in a clockwise direction. In this manner, the S twist yarn travels somewhat further and the filling thus contains a bit more 8 twist yarn than 2 twist yarn which compensates adequately for the Z twist yarn becoming slightly more twisted and the S twist yarn slightly less twisted during the pull-off. When a higher, even number of yarns is employed, in the making of such a fabric as, for example, that of Fig. 2, the cone arrangement is in the same manner as in Fig. 3, but duplicate each cone, with two Z twist cones below two 8 twist cones so that the multiple or group yarn made up of four ends is wound on the bobbin so as to smoothly and evenly pull therefrom and thus avoid yarn kinks which would otherwise mar the face of the directionally stiffened fabric -made therefrom. It will, of course, be appreciated that, the cones may be wound difierently than above described, in which case the cone arrangement will necessarily be varied, provided, of course, that the lower cone (or cones if four or six be employed) be so twisted and wound that the pull-off from the lower cone (or cones) results in the yarn (or yarns) being more tightly twisted during the pull-off, with the yarn (or yarns) from the upper cone (or cones) becoming slightly less twisted during the pull-off.

, is frame dried.

' Another means of substantially, or even entirely, neutralizing fabric curl is to use balanced plied, cabled, or hawsered reactive yarns in which groups a plurality of S twist yarns are wound or vice versa, so as to 6 ing little or no twist, such as modified low-twist cotton rovings, or synthetic continuous-filament very low-twist reactive yarns.

I have also discovered that the effect of increased grouping of reactive yarns has a surprising effect on the stillness of the fabrics in that increased grouping apparently increases the stiffness linearly, for example, a 48 x 48 (14s and 16s yarns) construction of reactive singles yarn in the filling has a fiexural rigidity rating of the order of 5000-6000 flexometer units (Pierce in milligram centimeters, herein abbreviated as "P. m. 0.") A 48 x 24 construction throwing two ends of similar yarns (but with one 8 and one 2) per pick so that the actual end count is the same as in the 48 x 48 construction just referred to, has a fiexural rigidity rating of the order of 10,000-12,000 fiexometer units P. m. c. It is further found that a 48 x 12 construction containing four ends of similar yarns (but with two 8 and two 2) per pick, and thus having an actual end count of 48 x 48, as with the two fabrics just referred to, has a fiexural rigidity rating of about 20,000-25,000 fiexometer units P. m. c. This most surprising increase in fiexural rigidity resulting from simply grouping similar yarns (of the same aggregate weight as though used singly) is a most useful feature in the manufacture of preferred forms of fabrics of this invention, and provides a ready means for securing practically any degree of-stiffness reasonably to be desired in yard goods and commercial fabrics for ordinary purposes, and 'without materially altering fabric thickness.

The following are typical examples of fabrics made in accordance with the invention:

ing substantially no curling tendencies and pronounced directional stiffness in the filling can be.

prepared as follows:

The warps are spun from raw cotton, sized and mounted on the loom beam in the regular manner of the textile trade. These gray yarns are unreactive to the swelling and stiffening agent. One-half the required weight of filling yarns is prepared with an S twist and one-half with a Z twist. These yarns are put in skein form and are kier boiled and bleached in the usual manner. For example, they may be boiled at 15 lbs. pressure for twelve hours using 5% caustic, 1% soap, and 1% sodium silicate, and then rinsed and bleached at F. using a solution containing 0.2% available chlorine. The yarns are then wound by any suitable mechanism on to the filling bobbins. This fabric must be woven on a boxloom in order to deposit 8 and Z twist yarns as single yarns (or S twist groups and Z twist groups) in the filling. The filling yarns will be deposited 8, Z, S, 2, etc., or S, 8, Z, 2, etc., according to the type of box-loom used.

The fabric solution of zinc chloride concentrated to about 70% and batched in a box for an hour or more. At the end of that time the zinc chlorideis leached out with water in a jig and the fabric At this point a surprising is: silience and rigidity in the filling is apparent.

If it is desired to boil and bleach the fabric to clean up the gray warp yarns thiscan be done by the standard methods without destroying. the directional stiffness caused by the filling yarns. Samples of this fabric have a fiexural rigidity rating of approximately 230 P. m. c. warpwise' and a rating of approximately 6,500 P. m; c. fillingis now ready for impregnation with I the gelatinizing agent. It is padded through a wise, providing a fabric with a stiffness ratio of about 30 to 1.

Example IL-An fnterlining material used in clothing in lieu of haircloth is woven with an actual end count of 48 x 48, two filling ends being thrown with each pick, as previously described, so that with the filling yarns thus grouped there is obtained a construction value of 48 x 24, two ends per pick. The warp yarns consist of 14s natural gray yarns and the filling is of 16s bleached yarns, half s twist and half Z twist, each filling .pick including one s and one Z twist yarn combined by the mechanism of Fig. fabric is impregnated with a concentrated solution of zinc chloride, batched for several hours. and then leached with cold water. After the zinc chloride is entirely removed, it is dried in a frame. The fabric is woven 39 and finished to 38" with a running weight of 294 yds. per lb. Samples of this fabric have a fiexural rigidity rating of approximately 100 P. m. c. warpwise and a rating of approximately 12,000 P. m. c. fillingwise, providing a fabric with a stiffness ratio of 120 to 1.

Example III.An 80 x 44 four-leaf 2/2 twill (13s and 8s yarns) weighing 1.5 yds. per 1b., suitable for use as an interlining fabric, having pronounced warpwise stiffness and no detectable curling tendencies, is prepared as follows:

The non-reactive filling yarns, which are to be gray, are spun and woven in the normal way. All of the warp yarns are to be scoured and bleached, so as to be reactive to the swelling agent. One-half of these latter yarns are 8 twist'and one-half are 2 twist, and so balance the curling tendencies imparted by each other. Thus, the finished fabric will have pronounced stiffness in the warp and it will not curl. In

in this example the warp yarns drawn in as $282 or 8822, thus producing a warpwis directional stiffness without curl. preparation of the loom, beam is easily accomplished by having one set of these yarns (either 8 or Z) tinted in the last rinse after bleaching. The yarns are then Wound on spools, and thence into section beams, each section beam bearing exclusively either 8 or Z twist. Finally, these beams are mounted behind the slasher (which applies a starch size, preferably containing. no oil, wax, or tallow) and combined during sizing by being wound up.onto loom beams in the desired order. After the fabric is woven, it is desized, dried, and impregnated as described in Example II. As before, a final scouring and bleaching operation may be performed to clean these filling yarns. Samples of this fabric have a flexural rigidity rating of approximately 11,000 P. m. c. warpwise and a rating of approximately 400 P. m. c. fillingwise, providing a fabric with a stiffness ratio of 30 to 1.

Example IV.A 5.0 yard 48 x 48 sheeting (21s cotton yarn warp, and 200 denier rayon filling yarn made up of continuous filament viscose rayon) having pronounced directional stiffness in the filling and essentially no curling tendencies. and suitable for use as an interlining fabric, may be prepared as follows:

In this fabric, curling characteristics are done away with by the use of continuous filament low,- twist rayon in the filling. The warps are prepared in the standard way using gray (unscoured) cotton. After the fabric is woven it is subjected to the fusing treatment in accordance with details given in previous examples. The rayon is fused by the chemical treatment, wherethis fabric have a 3. After weaving, the

- what more than the one inch as the gray cotton is not affected. Samples of flexural rigidity rating of approximately 200 P. m. c. warpwise and a rating of approximately 7,250 P. m. c. fillingwise, providing a fabric with a stiffness ratio of 36 to 1.

Example V.-A 60 x 34 marquisette having substantially no curling tendencies and pronounced directional stiffness in the warp can be prepared as follows:

The filling yarns are spun from 50s combed yarns in the regular manner. These yarns are in the gray and are un-reactive to the swelling and stiffening agent which may be any one of the gelatinizing agents described herein. The warp yarns are boiled and bleached 40s singles combed, one-half of them 8 twist and one-half of them 2 twist. The preparation of the loom beam is accomplished by the same method described in Example III, the ends being tied in SS, ZZ, or $2, SZ. The fabric is woven in the usual way, the leno effect being accomplished with doup heddles in the regular fashion. After the fabric is woven it is de-sized so as to remove the sizing from the warp yarns, dried, and then parchmentized as described in Example II. As before, the final scouring and bleaching operation may be performed if desired. Samples of this fabric have a fiexural rigidity rating of approximately 2000 P. m. c. warpwise and a rating of approximately 20 P. m. c. fillingwise, providing a fabric with a stiffness ratio of to 1.

The directionally stiff fabrics of this invention may conveniently be tested and compared from the standpoint of curl by cutting small squares therefrom and noting their deformation under standard conditions. For done by cutting from an ironed or smoothly pressed area of the fabric to be tested, a square sample 5" x 5", with adjacent sides thereof parallel with the warp and filling, respectively, conditioning the same at 70 F. and 70% relative humidity, and then observing its behavior when placed without restraint on a fiat surface or table.

As a practical matter and for most purposes,

-' fabrics may be regarded as having substantially thereof rises more than one inch above the supporting horizontal surface on. which it is placed. Fabrics made in accordance with the preferred practice of this invention are well within the one inch figure mentioned. However, the invention has considerable utility in the manufacture of many directionally stiff fabrics which curl somefigure referred to.

From the foregoing, it will be appreciated that the degree of directional stiffness for any given fused fabric depends fundamentally upon the fabric count and the yarn size, as well as upon the grouping, i. e., number of ends in each pick or heddle, as previously described. In general,

by my invention fabrics advantageously may be increased in stiffness directionally say, at least, five, or ten times, to even two hundred or more times, depending upon the weight of the fabric and the combination of the foregoing factors, according to the results desired, and this may be done in either the warp or filling direction. Ordinarily in practice and to secure the greatest output of a loom, it is preferable to stiffen the cloth fillingwise, but this is by no means universal, andin many cases it is desirable to provide a pronounced stiffness warpwise. Also, in the manufacture of certain fabrics w ch are to be given a pronounced stiffness fillingwise, it may be desirable to give them a slight stiffness warpwise, which may be done by inserting in the warp, among the gray or non-reactive warp yarns, a minor proportion of reactive yarns which are preferably neutralized betweenthemselves from a fabric curl standpoint. These yarns will impart to the finished fabric a minor degree of stiffness warpwise as compared with the directional weftwise stiffness. Similarly, it will be apparent that a fabric to be given a pronounced stiffness warpwise may also have included in its gray or non-reactive filling, a minor proportion of reactive filling yarns which ar preferably neutralizedbetween themselves from a fabric curl standpoint.

Another variant contemplated by the present invention involves the use of non-reactive yarns (in minor proportion) among those of the'set of yarns, warp or filling, to which it is desired to impart pronounced directional stiffness, this sometimes being desirable in order to supply a fabric of given stiffness and desired fineness of count for the purpose of either appearance or other desired lualities. It may likewise be found that in certain constructions too great stiffness is produced when all yarns in one direction are left reactive, in which case there may be substi-- tuted for some of the yarns (usually less than half) in said direction, gray cotton or other nonreactive yarns. Also, the stiffness of the reactive yarns may be reduced by the insertion by mixing of non-reactive fibers therein. If these non-reactive fibers are of wool or casein wool, the creaseresistance of the fabric is enhanced. For the same or other reasons corporate woolen or other non-reactive yarns in groups in which the remaining yarns are reactive.

It will be clear from the foregoing that this invention provides novel fabrics and novel methods of making such products with equipment and materials commonly available, and that the na. ture of the invention is such that these goods can be produced at an entirely reasonable cost. While I have herein described typical fabrics embodying this invention and suitable methods of making them, it will be understood that the invention is susceptible of embodiment in a great variety of forms within its spirit and scope, and that minor departures may be made from the methods above described while still following the r essential teachings of the invention.

Having thus described my invention, what I desire to claim as new is:

1. A woven fabric having much greater stiffness in one yarn direction than in prising sets of warp and filling yarns interwoven with each other, one of said sets consisting mainly of fused cellulosic oppositely twisted yarns materially stiffer than those of the other set and providing greater stiffness in their direction.

2. A woven ness in one yarn direction than in the other, comprising sets of warp and filling yarns interwoven with each other, one of said sets consisting mainly of fused cellulosic grouped yarns materially stiffer than those of the other set and providing greater stiffness in their direction.

3. A Woven fabric having much greater stiffness in one yarn direction than in the other, comprising sets of warp and filling yarns interwoven with each other, one of said sets consisting mainly of fused cellulosic grouped yarns with each group including at least one plied yarn and materially stifier than those of the other set and providing greater stiffness in their direction.

it may be desirable to inthe other, comprising sets of warp and filling yarns interwoven with each other. one of said sets consisting mainly of fused cellulosic grouped yarns materially stiffer than those of the other set and providing greater stiffness in their direction.

6. A woven fabric having substantially no tendency to curl and having much greater stiffness in one yarn direction than inthe other, comprising sets of warp and filling yarns interwoven with each other, one of said sets consisting mainly of fused cellulosic oppositely twisted grouped yarns materially stiffer than those of the other set and providing greater stiffness in their direction.

7. A woven fabric having at least fifty'times greater stiffness in one yarn direction than in the'other, comprising sets of warp and filling yarns interwoven with each other, one of said sets consisting mainly of fused cellulosic oppositely twisted yarns materially stiffer than those of the other set and providing greater stiffness in their direction, the yarns of the other of said sets being mainly unfused.

8. A woven fabric having much'greater stiffness in one yarn direction than in th other, comprising sets of warp and filling yarns interwoven with each other, one of saidsets consisting mainly of fused cellulosic oppositely twisted yarns materially stiffer than those of the other set and providing greater stiffness in their direction, the yarns of the other of said sets consisting of unfused cotton fibers.

9. A woven fabric having substantially no tendency to curl and having much greater stiffness in one yarn direction than in the other, comprising sets of warp and filling yarns interwoven with each other, the filling set consisting substantially of slack-twisted fused cellulosic continuous multi-filament singles yarns materially stiffer than those of the other set and providing at least five times greater stiffness in their direction.

10. A woven fabric adapted for treatment to provide greater stiifness in one yarn direction than in the other, comprising sets of warp and filling yarns interwoven with each other, one of said sets being characterized by right and lefthand twists and lulosic yarns reactive to fusing treatment to provide greater stiffness in their direction and the other set consisting mainly of yarns non-reactive to fusing treatment.

11. A woven fabric having much greater stiffness in one yarn direction than in the other. comprising sets of war and filling yarns interwoven with each other, one of said sets being characterized by right and left-hand twists and consisting of yarns made up mainly of fused cellulosic fibers materially stiffening the yarns of their set and providing greater stiffness in their yarn direction.

12. The method of making a directionally stiff fabric having much greater stiffness in one yarn direction than in the other which consists consisting mainly of fusible cel- I in providing sets of warp and fllling.yarns, one of said sets being characterized by right and lefthand twists and with the major portion of the yarns consisting mainly of reactive cellulosic fibers and the major portion of the yarns oi the second of said sets consisting mainly of non-reactive flbers, weaving together said sets to form a base fabric and then fusing the reactive fibers of said first set of yarns and finally drying the same, thereby materially stiffening the same to impart greater stiffness in their direction.

13. A woven fabric having much greater stiff ness in one yarn direction than in the other, comprising sets of warp and filling yarns interwoven with each other, one of said sets consisting mainly of fused cellulosic oppositely twisted singles yarns materially stifl'er than those oi the other set and providing greater stifiness in their direction.

14. A woven fabric having much greater stiffness in one yarn direction than in the other; comprising sets of warp and filling yarns interwoven with each other, one of said sets consisting main- 1y of fused regenerated cellulose oppositely twisted yarns materially stifler than those-of the other set and providing greater stiflness in their direction.

15. A woven fabric having much greater stiflness in one yarn direction than in the other, comv 12 prising sets 0! warp and filling yarns interwoven with each other, one of said sets consisting mainly of fused regenerated cellulose grouped yarns materially stifler than those 01' the other set and providing greater stiflness in their direction.

16. A woven fabric having much greater stillness in one yarn direction than in the other, comprising sets of warp and filling yarns interwoven Y with each other, one or said sets consisting mainly of fused regenerated cellulose singles yarns materially stifier than those of the other set and providing at least five times greater stiflness in their direction.

17. A woven fabric having at least five times greater stiffness in one yarn direction than in the other, comprising sets 01' warp and filling yarns interwoven with each other, one of said sets including gelatinized cellulose yarns suincient in number and size to provide said greater stifiness in their direction.

18. A woven fabric having at least five times greater stiffness in one yarn direction than in the other, comprising sets 01' warp and filling yarns interwoven with each other, one of said sets consisting mainly of gray cotton yarns and the other of said sets including gelatinized cellulose yarns sufiicient in number and size to provide said greater stiffness in their direction.

ROSS C. WHITMAN. 

